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Animal health experts discuss merits of vaccination against bird flu

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  • Animal health experts discuss merits of vaccination against bird flu

    Animal health experts discuss merits of vaccination against bird flu by Katia Dolmadjian
    Thu Mar 22, 7:43 AM ET



    VERONA, Italy (AFP) - Culling remains the best strategy to combat bird flu, while the less radical and more effective option of vaccination remains problematic in many countries, the head of the World Organisation for Animal Health (OIE) said Thursday.

    "When a country has sufficient means to intervene rapidly against an outbreak of the disease or can compensate poultry farmers for culled birds, you don't need vaccination because you use culling to solve the problem," OIE Director-General Bernard Vallat said on the sidelines of a gathering of public health experts in Verona, Italy.

    "You can vaccinate 'in rings,' that is encircling a bird flu outbreak, a group of villages for example. And when that doesn't work and the virus manages to escape, we recommend total 'blanket' vaccination to try to immunise all the animals," he added.

    The three-day conference -- organised by the UN Food and Agriculture Organisation (FAO), the OIE and two Venice regional animal health bodies -- which was to conclude on Thursday allowed experts from around the world to compare notes on the use of vaccination to combat bird flu.

    Since 2003, the deadly H5N1 strain has claimed at least 171 lives around the world, including 66 in Indonesia.

    Both FAO and OIE stressed that while strategies for fighting bird flu have proved effective, the key remains the political will of each affected country to implement them.

    "There are still three countries that are not capable of managing the situation: Indonesia, Egypt and Nigeria, which harbour reservoirs of the virus that can take off elsewhere," Vallat warned.

    Joseph Domenech, the FAO's chief veterinarian, said: "The lack of a national strategy, the lack of political involvement and the disorganisation of these countries mean that lots of outbreaks, as well as human cases of the disease, arise." He said he had "the greatest concern" about Indonesia.

    Bird flu is not expected to see a burst in outbreaks this year comparable to 2006, the experts here say, while stressing that the fight against the virus must carry on with the same intensity.

    "Obviously we don't have a crystal ball, but you can say we are not in the situation of 2006," when bird flu took hold in Africa, Domenech told AFP.

    Vallat added: "On the medical level you see a reduction in terms of viral quantity. The presence of the disease in the population of wild birds is lower than last year when there was a surge in the virus."

    He said: "There are for example many fewer dead birds wherever you are in the world, and so the virus is circulating less. So we don't expect a new explosion of outbreaks in 2007, although there is still the danger of localised phenomena."

    Wild birds "have perhaps learned to resist the virus naturally," he said, or the deadly H5N1 strain may be declining, since "all strains arise and then die one day."

    Domenech of the FAO said, for his part: "Globally, alert systems of both detection and reaction are now much faster in the majority of the affected countries, and the responses are much better."

    But it would be "unrealistic" to think that the virus will be completely eradicated soon, since it "continues to circulate and can reappear at any time," Domenech said.

    "There is still the risk of a pandemic virus," he said. "Monitoring will have to be maintained for years. And we'll have to live with this virus as we live with lots of other diseases, even if this one is a little special."

    Vallat warned that the vaccine loses effectiveness or becomes entirely useless if the "cool chain" is broken during transport.
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  • #2
    Re: Animal health experts discuss merits of vaccination against bird flu

    Vallat added: "On the medical level you see a reduction in terms of viral quantity. The presence of the disease in the population of wild birds is lower than last year when there was a surge in the virus."

    He said: "There are for example many fewer dead birds wherever you are in the world, and so the virus is circulating less. So we don't expect a new explosion of outbreaks in 2007, although there is still the danger of localised phenomena."

    Wild birds "have perhaps learned to resist the virus naturally," he said, or the deadly H5N1 strain may be declining, since "all strains arise and then die one day."
    Has actual testing of wild birds proven there is less asymptomatic H5N1 circulating in wild birds? Is there alsoless H5N1 in the internal viral segments?

    I would assume few wild birds dying is indicative of successful adaptation. We just need to look at the birds flying out of Qinghai in spring 2005 - yes many died, but thousands adapted and kept flying as asymptomatic carriers.

    How many strains arise, then die out without infecting a significant portion of the host species to which they've adapted? (i.e., after herd immunity is established) Travel logs showing the long lasting recycling of polymorphisms have convinced me that those little segments never die - they're just socializing with a new crowd for awhile.

    Until I read that most sequences don't have the NS1 & cleavage mutations, I will NOT feel safe.

    But I'd LOVE to be wrong.

    .
    "The next major advancement in the health of American people will be determined by what the individual is willing to do for himself"-- John Knowles, Former President of the Rockefeller Foundation

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    • #3
      EGYPT - On poultry vaccines in Egypt...

      Egypt to Present Its Bird Flu Experiment in Italy Sunday, March 19, 2007

      Egypt will take part in the conference on the use of vaccines as a means of controlling the spread of bird flu. The event will be held on Sunday, March 19 in Verona, Italy.

      The Egyptian delegation will present Egypt's strategy in using vaccines to prevent the spread of the infection of avian influenza. The delegation will also report on the epidemic status of the disease in Egypt in 2007 as compared to 2006.

      Figures representing poultry infection in 2007 have receded in comparison with those of 2006. In 2006, the bird flu virus affected 845 farms, 266 cases of domesticated poultry and 5 zoo cases. In 2007, only 9 farms have been affected and 58 cases of domesticated poultry. No zoo cases have been reported so far.

      The recession of the disease is attributed to the attempts made to raise poultry-breeders' awareness in rural areas.

      ...when you have eliminated the impossible, whatever remains, however improbable, must be the truth. - Sherlock Holmes

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      • #4
        Re: EGYPT - On poultry vaccines in Egypt...

        Originally posted by Theresa42
        Egypt to Present Its Bird Flu Experiment in Italy Sunday, March 19, 2007

        (...)

        Figures representing poultry infection in 2007 have receded in comparison with those of 2006. In 2006, the bird flu virus affected 845 farms, 266 cases of domesticated poultry and 5 zoo cases. In 2007, only 9 farms have been affected and 58 cases of domesticated poultry. No zoo cases have been reported so far.

        (...)

        http://birdflu.sis.gov.eg/html/flu01021187.htm
        From the BBC 'File on 4' program:
        Only half of the last year's 110 outbreaks of avian flu were reported. [I think that's the number for only Al Fayyum governorate.]

        The rest were discovered by spot checks and officials worry this may be only a fraction of the total....

        http://news.bbc.co.uk/1/hi/programme..._4/6441899.stm
        ...when you have eliminated the impossible, whatever remains, however improbable, must be the truth. - Sherlock Holmes

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